狭义相对论中动尺收缩效应之认识

动尺收缩是狭义相对论时空观的经典效应之一,本文从一道例题的错误解法出发,阐述狭义相对论中同时的相对性是形成动尺收缩效应的原因。     

Decreasing pores in a laser cladding layer with pulsed current

A pulsed current is introduced into the traditional coaxial laser cladding process to decrease the porosity of the cladding layer. The magneto contraction force caused by pulsed current exerted on the molten pool squeezes the gas out and compensates the shrinkage during molten pool solidification. As a result the porosity of the cladding layer is decreased to an extremely low degree. Simultaneously, the grain of the cladding layer is finer with the added supercooling degree with pulsed current. The microhardness of an equiaxed zone in the cross section of a cladding layer also increases.     

激光再现的物体“站立式”显示反射全息图的研究与制作

设计了一种记录和再现光路,实现了物体“站立”在全息图上的特殊观看效果。利用激光再现全息图的优点,针对卤化银乳胶在处理过程中的收缩特性,通过利用全息图处理工艺人为控制乳胶收缩量的方法,实现了用特定波长激光再现反射全息图的目标。设计记录波长632．8nm ,再现波长532nm。针对因乳胶收缩带来Bragg条件变化,计算了角度偏移量,给出了记录和再现条件,利用两步法记录了反射全息图,实现了预期的变波长激光再现、物体“站立式”显示效果。     

MT/MPO光纤连接器的新发展

本文介绍近年来为了适应高速和大容量光纤通信系统中高密度和高效率的互连布线的需要 ,日本住友和藤仓两家公司在 MT/MPO光纤连接器方面所进行的研究开发工作。研究重点在这些连接器中的关键部件MT套筒的改进。采用了注塑成形的 PPS新材料来制造套筒 ,以取得超低而稳定的介入损耗 ;提出了在连接端面附近的导引孔周围打倒角 ,以改善反复接插的耐久性。引入了最大达 16芯的单维 MT连接器和最大达 60芯的 2 -维阵列 MT连接器 ,以代替用多个 12芯 MT套筒的大芯数连接器 ,显著增加了光纤密度。开发了 2 -维阵列 MT连接器用的 2 4芯扁光纤带光缆代替圆光缆。文章介绍了这些新开发的产品的光学、机械和环境等方面的各项性能     

二次半定规划问题及其投影收缩算法

In this paper,we discuss the relations among the quadratic semi-definite programming problem,the linear semi-definite porgramming and the linearquadratic semi-definite programming problem.The duality theories are presented.After proving the equivalence of its optimality conditions and monotonous linear variational inequalities,we use the projection and contraction algorithms to solve(QSDP),We present the algorithms and its convergence analysis.     

THE INFLUENCE OF SHRINKAGE AND MOISTURE DIFFUSION ON IDEALIZED TOOTH STRUCTURE INVOLVING DEBONDING DAMAGE

This study highlights the joint effect of early polymerization shrinkage and longtermmoisture diffusion on the behavior of the restoration-tooth structure. The interphase debonding between particle and polymer resin in dental composite is taken into account by introducing the damage variable. The idealized model is designed and constructed for representing the restorationtooth structure, which consists of enamel, dentin, composite and interphase, each considered as homogenous material. The simulation is carried out using the general-purpose finite element software package, ABAQUS incorporated with a user subroutine for definition of damaged material behavior. The influence of Young‘s moduli of composite and interphase on stress and displacement is discussed. The compensating effect of water sorption on the polymerization shrinkage is examined with and without involving damage evolution. A comparison is made between the influence of hyper-, equi- and hypo-water sorption. Interfacial failure in the specific regions as well as cuspal movement has been predicated. The damage evolving in dental composite reduces the rigidity of composite, thus in turn reducing consequent stress and increasing consequent displacement. The development of stresses at the restoration-tooth interface can have a detrimental effect on the longevity of a restoration.     

收缩到一点的一类曲线流

处理由偏微分方程描述的新的平面曲线流：DX/Dt=β（k）N，X（μ，0）=X0（μ），当初始曲线X0（μ）是凸的Jordan曲线和β(k)满足适当的条件时，应用偏微分方程中的最大值原理和先验估计，证明了发展曲线的周长和面积同时收缩，最终它们都收缩到一点。     

夏普收缩电脑显示器业务 日系退出乃大势所趋

2005年8月26日消息，经南京夏普电子有限公司的一位负责人证实，“液晶之父”夏普正在考虑退出除日本本土外的全球电脑液晶显示器市场，将重点转向双屏液晶显示器等具有高附加值的产品线上。